Neuromuscular fatigue in healthy muscle: Underlying factors and adaptation mechanisms

AbstractObjectivesThis review aims to define the concept of neuromuscular fatigue and to present the current knowledge of the central and peripheral factors at the origin of this phenomenon. This review also addresses the literature that focuses on the mechanisms responsible for the adaption to neuromuscular fatigue.MethodOne hundred and eighty-two articles indexed in PubMed (1954–2010) have been considered.ResultsNeuromuscular fatigue has central and peripheral origins. Central fatigue, preponderant during long-duration, low-intensity exercises, may involve a drop in the central command (motor, cortex, motoneurons) elicited by the activity of cerebral neurotransmitters and muscular afferent fibers. Peripheral fatigue, associated with an impairment of the mechanisms from excitation to muscle contraction, may be induced by a perturbation of the calcium ion movements, an accumulation of phosphate, and/or a decrease of the adenosine triphosphate stores. To compensate for the consequent drop in force production, the organism develops several adaptation mechanisms notably implicating motor units.ConclusionFatigue onset is associated with an alteration of the mechanisms involved in force production. Then, the interaction between central and peripheral mechanisms leads to a series of events that ultimately contribute to the observed decrease in force production

Evaluating the quality of social work supervision in UK children's services: comparing self-report and independent observations

Understanding how different forms of supervision support good social work practice and improve outcomes for people who use services is nearly impossible without reliable and valid evaluative measures. Yet the question of how best to evaluate the quality of supervision in different contexts is a complicated and as-yet-unsolved challenge. In this study, we observed 12 social work supervisors in a simulated supervision session offering support and guidance to an actor playing the part of an inexperienced social worker facing a casework-related crisis. A team of researchers analyzed these sessions using a customized skills-based coding framework. In addition, 19 social workers completed a questionnaire about their supervision experiences as provided by the same 12 supervisors. According to the coding framework, the supervisors demonstrated relatively modest skill levels, and we found low correlations among different skills. In contrast, according to the questionnaire data, supervisors had relatively high skill levels, and we found high correlations among different skills. The findings imply that although self-report remains the simplest way to evaluate supervision quality, other approaches are possible and may provide a different perspective. However, developing a reliable independent measure of supervision quality remains a noteworthy challenge

Influence of exercise intensity and joint angle on endurance time prediction of sustained submaximal isometric knee extensions

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Influence of ankle plantarflexor fatigue on postural sway, lower limb articular angles, and postural strategies during unipedal quiet standing

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Differences in lower extremity muscular coactivation during postural control between healthy and obese adults

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Changes in posture associated with postural control impairment induced by ankle plantarflexor fatigue during unipedal quiet standing

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Attentional focus influences postural control and reaction time performances only during challenging dual-task conditions in healthy young adults

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Attentional Demands Associated With Postural Control Depend on Task Difficulty and Visual Condition

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